All checkboxes are disabled, i.e. I cannot tick them with mouse: screenshot
If I press "Mark all" and "Submit" then I get redirected to "Your preferences have been updated"
but if I reopen the above URL, all checkboxes will still be disabled.
(I've also tried deleting all site cookies but the problem remains).
This is an issue most importantly because I can no longer get email notifications when someone replies to a topic to which I've subscribed.